DR. Sofian Awamleh

1. Pulmonary Ventilation
DR. Sofian Awamleh

2. Parts of the
Respiratory System
and their Function

4. A. The upper
respiratory system
o The nose,
o Nasal
o Cavity,
o Paranasal
sinuses.
o Pharynx
B. The lower
respiratory system
o The larynx.
o trachea.
o Bronchi.
bronchioles
o Alveoli of the
lungs

5. Respiratory system consists of the organs that help to
breathe.
Respiration also known as breathing : the process
which delivers oxygen from the external atmosphere to the
body and removes the carbon dioxide from body and
expels out .

6. MAIN PARTS OF RESPIRATORY
SYSTEM AND THEIR FUNCTIONS

7. The nose
The externally
visible portion of
the nasal region
Is made up of bone,
cartilage, skin,
muscle, and mucous
membranes
External part
called: Nostrils

8. 1-The nostrils:
Nostrils are involved in
air intake where air is
warmed and humidified
and filtered.

9. The tiny hairs called cilia
filters out dust and other
particles present in the
air and protects the nasal
passage and other regions
of the respiratory tract.

10. The pharynx connects the nasal cavity and
mouth superiorly to the larynx and
esophagus inferiorly.
The laryngopharynx is an air and food
passageway that lies directly posterior
to the epiglottis, extends to the
larynx, and it is continuous inferiorly
with the esophagus.
2- The Pharynx

11. The larynx attaches superiorly
to the hyoid bone, opening
into the laryngopharynx, and
attaches inferiorly to the
trachea.
The larynx provides an open
airway, routes food and air
into the proper passageways,
and produces sound through
the vocal cords.
3- The Larynx

12. 4-Trachea:
The trachea is
also known as
windpipe.
The trachea
filters the air we
inhale and
branches into the
bronchi.

13. 5- Bronchi:
The bronchi are
the two air tubes
that branch off
of from the
trachea and carry
atmospheric air
directly into the
lungs

14. 6-Lungs:
The main organ of
the respiratory system
is lungs. Lungs are the
site in body where
oxygen is taken into
and carbon dioxide is
expelled out..

15. 7- Alveolus:

16. Alveolus is the
tiny sac like
structure present
in the lungs which
the gaseous
exchange takes
place.

17. 8- Diaphragm:
When we breathe in the diaphragm
contracts and flatten out and pull
downward. Due to this movement the
space in the lungs increases and
pulls air into the lungs.
When we breathe out, the diaphragm expands
and reduces the amount of space for
the lungs and forces air out.
A dome-shaped muscle located at
the bottom of the lungs.

19. Pulmonary
Ventilation

20. The major four functions of respiration
1) Pulmonary ventilation: inflow and out
flow of air between the atmosphere
and the lung alveoli.
2) Diffusion of oxygen and carbon
dioxide between the alveoli and the
blood

21. 3) Transport of oxygen and carbon
dioxide in the blood and body fluids
And from the body tissues cells.
4) Regulation of ventilation and
other facts of respiration.

22. .
Mechanics of pulmonary ventilation
The lung can be expanded and contracted in two
ways:
1) Downward and upward Movement of
diaphragm to lengthen and shorten the
chest cavity.

23. 2) Elevation and depression of the
ribs to increase and decrease the
anteroposterior of chest cavity.

24. Normal quiet breathing is accomplished
almost entirely by movement of the diaphragm
a. During inspiration, contraction of the
diaphragm pulls the lungs downward.
b. During expiration, the diaphragm simply
relaxes, and the elastic recoil compresses
the lungs and expels the air.

26. Respiratory muscles and their role in
respiration :
,
1)Muscles that elevate the chest cage are
classified as muscles of inspiration.
2) Muscles that depress the chest cage are
classified as muscles of expiration.

28. (1) sternocleidomastoid muscles, which lift upward on
the sternum.
(2) anterior serrati, which lift many of the Ribs.
(3) Scaleni , which lift the first two ribs.
The most important muscles that raise the rib
cage are the external intercostal ,
in addition these muscles support the previous
process :

30. The muscles that pull the rib cage
downward during expiration are:
(1) abdominal muscles : compress the
abdominal cavity upward against the
diaphragm up , and push air out of lungs.
(2) internal intercostal muscles: pull the
ribs downward and inward.

31. Inspiration Expiration
1.Diaphragm contracts
pushing downward.
2.Lungs expand as pressure
inside chest decreases.
3.Air drawn in through nose
and mouth.
1. Diaphragm relaxes
pushing upward.
2. Lungs made smaller
and more pressurized by
relaxing diaphragm.
3. Air passes out through
nose and mouth.

32.  Pleural pressure: pressure of the fluid in the thin
space between the lung pleura and the chest
pleura; there is a slight suction so the pressure is
negative.
 Alveolar pressure: pressure of the air inside the
lung alveoli
 Transpulmonary pressure: difference between the
pleural and alveolar pressures (recoil pressure).
Movement of Air In and Out of the Lungs and the
Pressures That Cause the Movement

33. Changes in lung volume, alveolar pressure, pleural pressure, and transpulmonary
pressure during normal breathing

34. Compliance of the Lungs
The extent to which the lungs will expand for each
unit increase in transpulmonary pressure.
Compliance Diagram of the Lungs
1. Inspiratory compliance curve.
2. Expiratory compliance curve.
3. Characteristics of the diagrams are depends on:

35. The characteristics of the compliance
diagram
(1) elastic forces of the lung tissue itself.
(2) elastic forces caused by surface tension of
the fluid that lines the inside walls of the alveoli
and other lung air spaces.

36. Compliance diagram in a
healthy person
Comparison of the compliance of saline
and air-filled lungs when the alveolar
pressure is maintained at atmospheric
pressure and pleural pressure is changed

37. Surfactant, Surface Tension, and Collapse of the
Alveoli.
Principle of Surface Tension.
When water forms a surface with air, the water molecules
on the surface of the water have an especially strong
attraction for one another.
As a result, the water surface is always attempting to
contract. This is what holds raindrops together: a tight
contractile membrane of water molecules around the entire
surface of the raindrop.

38. an elastic contractile force of the entire
lungs
the alveoli trays to collapse.
the water attempts to force the air out of
the alveoli through the bronchi
Surface tension elastic force

39. Secreted by special surfactant-secreting epithelial
cells called type II alveolar epithelial cells.
Surfactant: is surface active agent in water,
which reduces the surface tension of water.
Surfactant and Its Effect on Surface Tension

40. Surfactant is a complex mixture of several
phospholipids, proteins, and ions. The most important
components are the phospholipid
Type II alveolar epithelial cells
These cells are granular, containing lipid inclusions
that are secreted in the surfactant into the alveoli.

41. If the air passages leading from the alveoli of the
lungs are blocked, the surface tension in the
alveoli tends to collapse the alveoli. This creates
positive pressure in the alveoli, attempting to push
the air out.
Pressure in Occluded Alveoli Caused by
Surface Tension.

42. Effect of the Thoracic Cage on Lung
Expansibility
• Compliance of the thorax and the
lungs
• Work of breathing :
1.Compliance or elastic work
2.Tissue resistance work
3.Airway resistance work

43. “Work” of Breathing

44. Expiration
Respiratory muscle contraction
Elastic recoil of the lungs and chest
cage
Inspiration

45. The work of inspiration can be divided into
three fractions:
(1) that required to expand the lungs against the lung
and chest elastic forces, called compliance work or
elastic work;
(2) that required to overcome the viscosity of the lung
and chest wall structures, called tissue resistance work;
(3) that required to overcome airway resistance to
movement of air into the lungs, called airway resistance
work.

46. Energy Required for Respiration.
During normal quiet respiration, only 3 to
5 %of the total energy expended by the
body is required for pulmonary ventilation.
But during heavy exercise, the amount of
energy required can increase as much as
50-fold, especially if the person has any
degree of increased airway resistance or
decreased pulmonary compliance.

47. Pulmonary Volumes and
Capacities

48. • Pulmonary Volumes
1. Tidal Volume : volume of air inspired or expired
with each normal breath; usually about 500 ml.
2. Inspiratory Reserve Volume : extra volume that can
be inspired over and above the tidal volume usually
about 3000 ml.
3. Expiratory Reserve Volume : maximum extra volume
that can be expired at the end of a normal tidal
expiration usually about 1100 ml.
4. Residual Volume : volume of air remaining in the
lungs after the most forceful expiration; usually about
1200 ml.

49. Pulmonary Capacities
1. Inspiratory Capacity = tidal volume +
inspiratory reserve volume about 3500 ml
2.Functional Residual Capacity =
expiratory reverse volume + residual volume
about 2300 ml
3. Vital Capacity= inspiratory reserve volume +
expiratory reverse volume = (4600) ml
4. Total Lung Capacity= Vital Capacity+ residual
volume = (5800) ml

50. Mucus Lining the Respiratory Passageways.
The mucus is secreted partly by individual
mucous goblet cells in the epithelial lining of
the passages and partly by small submucosal
glands.
Function:
keeping the surfaces moist, and traps small
particles out of the inspired air and keeps
most of these from ever reaching the alveoli.

51. Nervous and Local Control of the Bronchiolar
Muscles
1. Sympathetic ( dilation of the bronchi )
• Direct control of the bronchioles by sympathetic nerve fibers
is relatively weak because few of these fibers penetrate to
the central portions of the lung.
• The bronchial tree is very much exposed to norepinephrine
and epinephrine released into the blood by sympathetic
stimulation of the adrenal gland medullae.

52. 2. Parasympathetic( Constriction of the Bronchioles)
few parasympathetic nerve fibers derived from the
vagus nerves penetrate the lung . These nerves
secrete acetylcholine , when activated, cause mild
to moderate constriction of the bronchioles.
When a disease process such as asthma has already
caused some bronchiolar constriction.
When this occurs, administration of drugs that block
the effects of acetylcholine, such as atropine, can
sometimes relax the respiratory passages enough to
relieve the obstruction.

53. Local Factors Often Cause Bronchiolar
Constriction.
1. Histamine
2. Slow reactive substance of anaphylaxis.
Both of these are released in the lung tissues by
mast cells during allergic reactions.
They play key roles in causing the airway obstruction
that occurs in allergic asthma; this is especially true
of the slow reactive substance of anaphylaxis.

54. Disorders of the respiratory system
1. Chronic infection : caused by inhaling smoke or other
substances that irritate the bronchi and bronchioles
2. The infection, excess mucus, and inflammatory edema of the
bronchiolar epithelium.
3. The obstruction of the airways causing difficulty to expire .